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LINE-1 repeats are a defining feature of the Xce.

During early development, female mammals inactivate one X chromosome to balance their X-linked gene dosage with males. While allelic choice is random in inbred mouse populations, choice can be significantly skewed in interstrain hybrids. The genetic basis of skewing has long been attributed to the mysterious "X chromosome controlling element(s)" (Xce) with different strengths among species, subspecies, and strains. When two X-chromosomes with different Xce strengths are inherited by offspring, the X chromosome with the stronger Xce will have a higher probability of remaining active. Here, we provide evidence that L1Tf repeats-a subfamily of long interspersed nuclear elements 1-plays a role in determining Xce strength. L1Tf elements form a condensed core within the inactive X (Xi) territory. Mouse strains with varying Xce strengths differ in the L1Tf copy number on the X chromosome, with the strength of the Xce allele being inversely related to L1Tf copy number. L1Tf expression mediates the Xce effect. However, in contrast to a prior report, L1Tf RNA does not coat the Xi. Rather, L1Tf promotes condensation of the Xi core. Intriguingly, L1Tfs recruit and sequester YY1 from active genes, accelerating XCI in cis. Thus, L1Tf copy number, expression, and binding of YY1 are key defining features of the Xce. We propose a model in which the Xce influences the choice of Xist alleles by promoting YY1 binding to the nucleation site for the initiation of Xist spreading.

Animals

Sexual selection purges mutation load, but not overall genetic diversity, decreasing vulnerability to extinction.

Theory suggests sexual selection will enhance population viability by purging deleterious alleles. However, direct genomic evidence for this fundamental idea is scarce and contradictory. We combined long-term experimental evolution with whole-genome resequencing to directly test how sexual selection affects mutation load, genomic divergence, and extinction risk in small populations (maximum Ne = 40) of Tribolium castaneum. After 156 generations, populations evolving under strong sexual selection carried substantially fewer deleterious alleles than populations under weak sexual selection, based on both individual-level estimates of missense and nonsense variants and population-level Rxy analyses, indicating more efficient purging of deleterious alleles. In contrast, nucleotide diversity and runs of homozygosity were similar across treatments, indicating that purging acted most strongly on deleterious variation, and that reduced mutation load in these small populations under strong sexual selection was not explained by demographic effects. Importantly, population-level mutation load estimates best explained extinction risk under inbreeding, directly linking sexual selection to purging and population viability. Genome scans of high and low sexual selection populations revealed peaks of divergence, which included genes involved in courtship, sex discrimination, and seminal fluid proteins. Our results provide direct genomic evidence that sexual selection can reduce mutation load without eroding standing genetic diversity and thus adaptive potential, while driving adaptive divergence in reproductive traits. This beneficial purging may help explain the widespread prevalence of sexual reproduction in nature despite inherent costs and have important ramifications as to how we manage populations of conservation concern.

Animals

HRAS promotes mutant NRAS-driven transformation with codon and allele specificity.

Wild-type RAS family members determine the signaling and therapeutic response in cancers driven by mutant HRAS and KRAS because they activate alternate RAS effector pathways. Here, we found that the requirement for wild-type RAS to support mutant NRAS-driven transformation correlated with codon-specific differences in GTP hydrolysis. NRAS with mutations at either Gly12 (G12X) or Gly13 (G13X), which retained the GDP-GTP cycling function, had modest autonomous transforming potential. In contrast, NRAS with GTP-locking mutations at Gln61 (Q61X mutants) was uncoupled from receptor tyrosine kinase (RTK) input, rendering wild-type RAS an obligate partner for RTK-stimulated signaling and oncogenesis. In RASless cells expressing mutant NRAS, reintroduction of wild-type HRAS was sufficient to restore signaling and transformation. Global dependency mapping in human cancer cells revealed functional partitioning, wherein mutant NRAS promoted MAPK signaling and wild-type HRAS promoted PI3K-AKT survival signaling. Consequently, allele-specific or pan-RAS(ON) inhibitors synergized with inhibitors of proximal RTK signaling or of wild-type HRAS or KRAS to overcome this signaling plasticity. Pan-RAS(ON) and HRAS inhibition was synergistic for all NRAS mutants tested, with Q61X mutants showing greater sensitivity. These findings define the signaling partnership between mutant NRAS and wild-type HRAS as a targetable vulnerability and provide a biochemical blueprint for dual RAS inhibition in NRAS-mutated malignancies.

Humans

Sex- and age-specific associations of VEGFA polymorphisms with multiple sclerosis susceptibility.

AIM: To evaluate six VEGFA polymorphisms (rs1570360, rs699947, rs3025033, rs2146323, rs1413711 and rs833061) and serum VEGFA concentrations in 270 Lithuanian patients with multiple sclerosis (MS) and 270 matched healthy controls. METHODS: Genotyping was performed using real-time PCR, and serum VEGFA levels were measured by enzyme-linked immunosorbent assay. Statistical analyses were conducted using IBM SPSS version 31.0. RESULTS: Nominal differences in VEGFA genotype and allele distributions were observed in sex- and age-stratified analyses. Among females, the rs1413711 C allele was more frequent (p = 0.005), whereas the rs833061 C allele was less frequent (p = 0.006), in MS patients than controls. In participants aged >38 years, the rs1413711 C allele was also more frequent in MS cases (57.5% vs. 46.0%, p = 0.008). Logistic regression identified nominal associations, particularly for rs1413711, rs699947 and rs833061, but none remained significant after correction for multiple testing. Serum VEGFA levels were higher in MS patients than controls (p = 0.004). Nominal genotype-related differences in serum VEGFA levels and haplotype associations with reduced MS odds were also observed, but did not remain significant after multiple-testing correction. No consistent associations were found between VEGFA variants and clinical parameters. CONCLUSION: VEGFA genetic variation and elevated serum VEGFA may be associated with MS, but the genetic findings require confirmation in larger independent cohorts.

Humans

Cis-regulatory variation in the MdCKX6 promoter is associated with allele-specific expression and fruit size in apple.

Fruit size is a key determinant of apple fruit quality and market value and is strongly influenced by phytohormone-regulated cell proliferation and expansion during early fruit development. Cytokinin oxidase/dehydrogenase (CKX) enzymes regulate cytokinin homeostasis by irreversibly degrading active cytokinins, but the contribution of natural variation in CKX genes to fruit size remains poorly understood. Here, we identified MdCKX6 as a candidate regulator of fruit growth in apple (Malus domestica). MdCKX6 exhibited pronounced allele-specific expression during fruit development in the cultivar 'Royal Gala'. Sequence analysis identified a promoter SNP associated with differential promoter activity and allele-specific expression. Genotyping of diverse apple cultivars and wild Malus accessions revealed a significant association between MdCKX6 promoter genotype and fruit size. Cultivars carrying low-expression alleles produced larger fruits, whereas high-expression alleles were associated with smaller fruits. To investigate gene function, MdCKX6 was overexpressed in tomato, resulting in reduced fruit size. Histological analyses of the transgenic tomato fruit revealed smaller pericarp cells. Transcriptome analysis of transgenic fruits revealed widespread changes in genes associated with cell-cycle regulation, cell wall modification, hormone-related processes, and transcriptional regulation. Together, these results identify MdCKX6 as a potential negative regulator of apple fruit growth and reveal an association between cis-regulatory variants, gene expression, and fruit size. This study provides new insights into the role of cytokinin metabolism in fruit development and highlights regulatory variation in MdCKX6 as a potential target for apple breeding.

Malus

Subtle cortical thinning in the temporal pole in middle-aged APOE-ε4 and PICALM (rs3851179) AA/AG carriers without dementia.

The symptoms of Alzheimer's disease (AD) are caused by neurodegeneration and atrophy in particular brain regions, especially in the temporal lobe. However, the influence of genetic risk on cortical thickness prior to dementia onset, remains unclear. This study aimed to explore the relationship between AD genetic risk (related to APOE and PICALM genes) and cortical thickness in selected regions of interest (ROIs) in middle-aged individuals without dementia. Sixty-nine (N = 69) participants (34 females, 35 males; age: 55.45 ± 3.19) underwent magnetic resonance imaging (MRI). They were divided into three groups based on their genetic AD risk: A+ P+ (APOE/PICALM risk variants), A+P- (APOE risk variant, PICALM neutral variants), and the N group (APOE/PICALM neutral alleles). Cortical thickness was analyzed using CAT12 software (surface-based morphometry with the Destrieux atlas) based on T1-weighted MR images in five ROIs referred to as "the cortical signature of AD" in previous studies. The A+P- group had a thinner right temporal pole cortex than non-carriers after controlling for sex, age, and Raven's Progressive Matrices scores. Although this finding did not survive FDR correction across the 10 tested regions, it is consistent with our hypotheses and prior literature. No other differences in cortical thickness were found in the analyzed regions of AD "signature". The observed effect was restricted to single-risk APOE carriers without PICALM risk alleles. Therefore, further research is needed to understand the genetic interplay between these two genes in conferring AD risk.

Humans

Biallelic Variants in ATP1A4 Are Associated with Oligoasthenoteratozoospermia and Male Infertility.

Male infertility, often caused by structural and functional sperm defects, remains genetically unexplained in a substantial proportion of cases. ATP1A4 encodes a testis-specific isoform of the Na+, K+-ATPase, a membrane enzyme crucial for maintaining cellular ionic homeostasis. Previous studies on Atp1a4 knockout mice have demonstrated severe defects in sperm motility and flagellar architecture; however, the contribution of ATP1A4 variants to human male reproduction remains to be elucidated. In this study, we identified compound biallelic variants in ATP1A4, a missense variant (c.2578 T>A, p.Tyr860Asn) and a frameshift variant (c.2582del, p.Gly861Aspfs*5), in a patient presenting with severe oligoasthenoteratozoospermia. Both variants markedly affected ATP1A4 protein expression. Morphological analyses revealed coiled and folded flagella, disrupted mitochondrial sheaths, and irregular head morphology in the patient's spermatozoa. Expression profiling revealed that ATP1A4 was highly enriched in post-meiotic spermatids and localized along the entire flagellum of mature sperm in both humans and mice, indicating a critical role in flagellar assembly and structural integrity. Notably, intracytoplasmic sperm injection (ICSI) in this patient resulted in low fertilization efficiency and failed implantation, suggesting a potential adverse impact of ATP1A4 deficiency on sperm functional competence beyond motility. These findings broaden the genetic spectrum of oligoasthenoteratozoospermia and highlight ATP1A4 as a potential gene associated with human male infertility.

Male

A Letter Matters: ADRB2 rs1042713 c.46A Modulates Anti-osteogenic Effect of Epinephrine in Human Mesenchymal Stem Cells.

Osteoporosis (OP) is a systemic bone disease affecting millions worldwide, characterized by long-term asymptomatic development that manifests in low-energy fractures. Due to their high stability, genetic markers represent a promising strategy for early diagnostics. The ADRB2 rs1042713 polymorphism is one such marker, considered as a potential predictor for OP. Although the anti-osteogenic role of the β2-adrenergic receptor is well-established, debate continues on which allele (G or A) of this polymorphism drives bone deterioration. In this study, we examined the influence of the ADRB2 rs1042713 G/G and A/A variants on osteogenic differentiation in patient-derived mesenchymal stem cells (MSCs) under treatment with the endogenous agonist epinephrine. We show that epinephrine (whose levels are often elevated in comorbid conditions) drastically impairs osteogenic differentiation, specifically at the matrix mineralization stage in MSCs A/A. Epinephrine fails to activate the canonical β2-adrenergic receptor pathway and promotes receptor perinuclear and nuclear localization in MSCs A/A. Crucially, metformin, a common anti-diabetic drug, rescues this anti-osteogenic effect. These results open new perspectives for early diagnostics by identifying epinephrine sensitivity as a critical factor, while also suggesting a potential therapeutic strategy to counteract epinephrine detrimental effect in individuals carrying the ADRB2 rs1042713 A-allele.

Humans

DNM1L depletion leads to accelerated heteroplasmy shifting of m.10191C allele through ATG7-dependent pathways.

Nucleotide composition bias in mitochondrial DNA (mtDNA) makes the heavy strand prone to form a DNA secondary structure called a guanine quadruplex (G4). This secondary structure has been shown to inhibit polymerase processivity in vitro. We previously identified pathogenic mtDNA variants that lead to increased G4-forming propensity, including a T to C mutation at m.10191 (m.10191 T > C) that causes Leigh syndrome. Cells treated with G4 binding agent (G4BA) berberine show a reduction in m.10191C pathogenic heteroplasmy levels. To help better understand the underlying mechanism behind berberine-induced heteroplasmy shift, we examined the relationship between mitochondrial fission and berberine-mediated shift. Here we show that knockdown of the fission factor DNM1L leads to an accelerated heteroplasmy shift towards the healthy mtDNA allele, lowering m.10191C by 10% in 3 weeks, compared to the 5 weeks required for berberine alone. The specific mechanism involves ATG7, as knockdown of ATG7 is able to partially delay this accelerated heteroplasmy shift. Taken together, we show that DNM1L knockdown is able to accelerate berberine-induced m.10191C heteroplasmy shifting through an autophagy-related mechanism.

Humans

Association of ERBB4 and SHBG gene polymorphisms with polycystic ovarian syndrome in South Indian women: a case-control genetic analysis.

INTRODUCTION: Polycystic ovary syndrome (PCOS) is a multifactorial endocrinological disorder with a substantial genetic component. However, the role of genes involved in follicular development and androgen regulation remains incompletely understood, particularly in South Indian populations. This study aimed to evaluate how variations in the ERBB4 and SHBG genes affect PCOS risk. METHODOLOGY: A hospital-based case-control study was conducted among 400 South Indian women, comprising 200 women with PCOS and 200 age-matched healthy controls. Genomic DNA was extracted to study SNPs at ERBB4 (rs2178575 and rs1351592) and SHBG (rs1799941 and rs727428) using ARMS-PCR genotyping. The study compared genotype and allele frequencies between cases and controls while assessing their associations with allelic, homozygous, heterozygous, dominant, recessive, and over-dominant genetic models. Genotyping accuracy was confirmed by re-genotyping and Sanger sequencing of a subset of samples. RESULTS: The ERBB4 rs2178575 polymorphism demonstrated a significant association with PCOS, as the AA genotype and A allele combination increased risk across all three genetic models, including homozygous, recessive, and allelic models. The ERBB4 rs1351592 variant was associated with 3-fold higher risk of PCOS in heterozygous and GC carriers. The SHBG rs1799941 polymorphism showed a significant link to PCOS through its effects on heterozygous and allelic states, whereas rs727428 displayed no significant connection due to its monomorphic distribution. CONCLUSION: These findings suggest that polymorphisms in ERBB4 and SHBG may contribute to PCOS susceptibility in South Indian women in a locus- and model-specific manner, revealing the intricate genetic structure that defines this medical condition.

Humans

Assessing the Frequency of VEXAS-Related Canonical UBA1 Mutations in Myelodysplastic Syndrome Patients.

OBJECTIVES: Somatic mutations in the UBA1 gene cause VEXAS syndrome, which presents with inflammatory and hematological symptoms. Case studies show a strong overlap between VEXAS and myelodysplastic syndrome (MDS). Recognizing VEXAS is important for differential diagnosis in patients with both inflammation and MDS, as accurate identification guides treatment. The study focuses on determining how often canonical UBA1 mutations linked to VEXAS occur in MDS patients. METHODS: Patients diagnosed with MDS were enrolled in the study, and genomic DNA was isolated from bone marrow FFPE samples. Molecular analysis was performed using a specifically designed ARMS-PCR approach. Additionally, protein-protein interaction (PPI) studies combined with bioinformatic analyses were carried out to explore potential links between UBA1 and pyroptosis. RESULTS: Among the 149 MDS patients analyzed, none exhibited high-Variant Allele Frequency (VAF) the canonical UBA1 point mutations linked to VEXAS syndrome. PPI analysis revealed a possible association between UBA1 and the NLRP3 inflammasome component. CONCLUSIONS: Expanding the sample size and using targeted NGS or ddPCR would improve mutation detection sensitivity and could reveal UBA1 canonical and non-canonical variants and more accurately estimate the frequency of VEXAS-related mutations in the MDS population.

Humans

Prevalence of POMC allele associated with obesity in feline population in Vietnam.

Feline obesity is an increasingly important health problem influenced by both genetic predisposition and husbandry practices. This study investigated the prevalence and phenotypic relevance of the feline proopiomelanocortin (POMC) c.28G > C (p.Gly10Arg) variant in a Vietnamese cat population and evaluated environmental factors associated with obesity. A total of 63 clinically healthy cats were classified as normal weight (body condition score [BCS] 5-6/9; n = 40) or obese (BCS ≥7/9; n = 23). Genotyping was performed using a newly developed PCR-restriction fragment length polymorphism assay and validated by Sanger sequencing. Ventral subcutaneous adipose tissue (VSAT) thickness was measured ultrasonographically as an objective indicator of adiposity. Genotyping revealed a high prevalence of the risk-associated C allele, with 45/63 cats (71.4%) carrying the GC genotype and 18/63 (28.6%) carrying the CC genotype, whereas the GG genotype was not detected, giving a Callele frequency of 64.3%. Obese cats had significantly greater body weight and VSAT thickness than normal-weight cats. Neuter status and ad libitum feeding were significantly associated with obesity, whereas diet type, housing, exercise frequency, and begging behavior were not. Although genotype distribution did not differ significantly between normal and obese cohorts, obese CC cats showed significantly greater VSAT thickness than obese GC cats, indicating an allele-dosage effect on adiposity. These findings suggest that the POMC c.28G > C variant is a useful risk-informative marker and that combining genetic screening with objective fat assessment may support earlier identification and prevention of feline obesity in Vietnam under routine laboratory conditions and guide personalized management strategies in practice.

Animals

Unravelling Ovarian Cancer: an analysis of the Influence of LRP1 and PAI1 Genetic Variations.

To assess the potential association between LRP1 (rs715948) and PAI1 (rs2227631, rs1799889) gene variation and ovarian cancer (OC) susceptibility. This study evaluated the genotypic and allelic distributions of LRP1 gene and PAI1 gene variants using Restriction Fragment Length Polymorphism (RFLP) analysis in 134&#xa0;&#xb0;C patients and 134 healthy controls. LRP1 (rs715948) showed a significant association with OC risk. The TC genotype was (OR&#x2009;=&#x2009;3.7823, 95% CI: 2.1732-6.5825, p&#x2009;<&#x2009;0.0001), and the CC genotype has (OR&#x2009;=&#x2009;2.1613, 95% CI: 1.0054-4.6459, p&#x2009;=&#x2009;0.0484). The C allele was significantly more frequent in cases (46%) than controls (32%) (OR&#x2009;=&#x2009;1.7684, 95% CI: 1.2443-2.5133, p&#x2009;=&#x2009;0.0015). For PAI1 (rs2227631), AG and GG genotypes showed no significant association (p&#x2009;=&#x2009;0.3519 and p&#x2009;=&#x2009;0.1165, respectively). PAI1 (rs1799889) AG genotype was (OR&#x2009;=&#x2009;5.855, 95% CI: 2.4663-13.9027, p&#x2009;<&#x2009;0.0001), while GG genotype showed no significance (p&#x2009;=&#x2009;0.1025). The dominant model of LRP1, (TC&#x2009;+&#x2009;CC) and C alleles, were significantly more frequent in OC cases, indicating a potential risk factor. In contrast, the dominant models (AG&#x2009;+&#x2009;GG) and G alleles of PAI1 (rs2227631, rs1799889) showed no significance with OC susceptibility. Genetic variation in LRP1 (rs715948) significantly associated with increased OC risk, particularly the TC and CC genotypes and C allele. The C allele of this gene is key markers linked to higher OC susceptibility. Whereas in PAI1 (rs2227631, rs1799889), dominant models (AG&#x2009;+&#x2009;GG) show no significance, association suggesting a less prominent role in OC susceptibility. These findings highlight LRP1 as a potential genetic biomarker for OC risk assessment, while the role of PAI1 variants warrants further investigation in larger sample size.

Humans

Variants in the interferon regulatory factor 5 gene confer genetic risk for systemic lupus erythematosus in a Han Chinese population.

BACKGROUND: Interferon regulatory factor 5 (IRF5), integral to interferon signaling pathways, has been identified as a susceptibility locus for systemic lupus erythematosus (SLE). Nevertheless, the relationship between IRF5 variants and SLE risk within the Han Chinese demographic remains inadequately characterized. MATERIALS AND METHODS: Genotyping of two functional single nucleotide variants (SNVs) in IRF5 was conducted in 167 individuals with SLE and 246 healthy controls utilizing sequence-specific primer polymerase chain reaction (PCR-SSP). Chi-square and Fisher's exact tests were employed to assess associations. RESULTS: The rs10954213 variant demonstrated a significant association with SLE susceptibility under the recessive model (GG vs. AG+AA, OR = 2.20, 95% CI: 1.30-3.75, p&#x2009;=&#x2009;0.003, adjusted p [pc]&#x2009;=&#x2009;0.030) and homozygous model (GG vs. AA, OR = 2.43, 95% CI: 1.36-4.42, p&#x2009;=&#x2009;0.003, pc = 0.032). Similarly, the rs2004640 variant was associated with an increased risk of SLE across allelic (T vs. G, OR = 1.66, 95% CI: 1.22-2.26, p&#x2009;=&#x2009;0.001, pc = 0.011), dominant (TG+TT vs. GG, OR = 1.77, 95% CI: 1.19-2.63, p&#x2009;=&#x2009;0.005, pc = 0.047), and homozygous models (TT vs. GG, OR = 3.72, 95% CI: 1.58-8.78, p&#x2009;=&#x2009;0.002, pc = 0.016). Haplotype analysis identified protective haplotype HT1 (A/G, OR = 0.54, 95% CI: 0.41-0.73, p&#x2009;<&#x2009;0.001) and risk haplotype HT4 (G/T, OR = 2.51, 95% CI: 1.42-4.42, p&#x2009;=&#x2009;0.001). CONCLUSIONS: These findings indicate that IRF5 gene variants substantially modulate susceptibility to SLE in the Han Chinese population. They hold potential as biomarkers for evaluating SLE risk and offer valuable perspectives into disease pathogenesis.

Adult